Glaucoma Practice Questions

Q: What type of laser is used in laser iridotomy?

Nd Yag laser. **Explanation:** **Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) laser** is the gold standard for performing a peripheral iridotomy (LPI). It is a **solid-state, photodisruptive laser** that works by creating a localized shockwave to punch a hole through the iris tissue. This creates an alternative pathway for aqueous humor to flow from the posterior to the anterior chamber, effectively bypassing pupillary block in Angle-Closure Glaucoma. **Analysis of Options:** * **Nd:YAG Laser (Correct):** Operates at a wavelength of **1064 nm** (infrared). It is preferred because it is non-thermal and can penetrate even dark, thick irides effectively. * **CO2 Laser:** Primarily used in dermatology and ENT for cutting or vaporizing tissue. It has high water absorption and is not used intraocularly for glaucoma. * **Excimer Laser:** A "cool" ultraviolet laser used in refractive surgeries like **LASIK and PRK** to reshape the cornea by photoablation. * **KTP (Potassium Titanyl Phosphate) Laser:** A frequency-doubled Nd:YAG (532 nm) that produces green light. It is used for photocoagulation (like retinal procedures) but is not the primary choice for iridotomy. **High-Yield Clinical Pearls for NEET-PG:** 1. **Indications:** Primary Angle Closure (PAC), PAC Glaucoma, and the fellow eye of a patient with an acute attack. 2. **Pre-procedure Medication:** **Pilocarpine** is used to stretch the iris (making it thinner and easier to penetrate) and **Apraclonidine/Brimonidine** to prevent post-laser IOP spikes. 3. **Preferred Site:** Usually placed in the superior periphery (11 or 1 o'clock) to be covered by the upper eyelid, preventing "ghost images" or diplopia. 4. **Complication:** The most common immediate complication is a transient **IOP spike** and localized **hyphema** (bleeding from the iris).

Q: What is the preferred drug for acute angle closure glaucoma?

Pilocarpine. **Explanation:** **Pilocarpine** is the definitive medical treatment for acute angle-closure glaucoma (AACG) because it is a **miotic (parasympathomimetic)**. In AACG, the peripheral iris obstructs the trabecular meshwork. Pilocarpine causes contraction of the iris sphincter muscle, which pulls the peripheral iris away from the angle, physically opening the drainage pathway and allowing aqueous humor to exit. *Note:* In very high intraocular pressure (IOP > 40-50 mmHg), the iris sphincter becomes ischemic and unresponsive to pilocarpine. Therefore, systemic hyperosmotics (like Mannitol) or Acetazolamide are often given first to lower IOP before pilocarpine can work effectively. **Why other options are incorrect:** * **Beta-blockers (e.g., Timolol):** While they help reduce aqueous production, they do not address the primary anatomical pathology (the closed angle). They are used as adjunctive therapy, not the definitive drug of choice. * **Atropine:** This is a **mydriatic** (dilates the pupil). It is strictly **contraindicated** in AACG because pupillary dilation further bunches the iris into the angle, worsening the blockage and potentially blinding the patient. **Clinical Pearls for NEET-PG:** * **Drug of choice to rapidly lower IOP:** Intravenous Mannitol (Hyperosmotic). * **Definitive/Permanent Treatment:** Laser Peripheral Iridotomy (LPI) – performed on both the affected and the fellow (prophylactic) eye. * **Classic Presentation:** "Halos around lights," "steamy cornea," and a "mid-dilated non-reactive pupil." * **Pilocarpine Side Effect:** Can cause "brow ache" due to ciliary muscle contraction.

Q: A coloured halo is seen in all conditions except:

Open angle glaucoma. **Explanation:** The perception of **colored halos** (iridescent vision) around lights is a clinical phenomenon caused by the diffraction of light as it passes through an edematous cornea or a lens with structural changes. **1. Why Open Angle Glaucoma (OAG) is the correct answer:** In **Primary Open Angle Glaucoma**, the rise in intraocular pressure (IOP) is typically slow, chronic, and painless. The corneal endothelium is usually able to compensate for this gradual rise, preventing significant corneal edema. Since the cornea remains clear and dehydrated, light diffraction does not occur, and colored halos are **not** a feature of OAG. **2. Analysis of other options:** * **Closed Angle Glaucoma:** During an acute attack, the IOP rises rapidly and severely. This overwhelms the corneal endothelial pump, leading to **corneal edema** (accumulation of fluid in the epithelial cells). This fluid acts as a diffraction grating, splitting white light into its spectral components (the "Fincham’s Test" can differentiate this from cataract). * **Cataract:** In early stages (immature or nuclear cataract), irregular refractive indices in the lens fibers or water clefts cause light scattering, leading to the perception of halos. **Clinical Pearls for NEET-PG:** * **Fincham’s Test:** Used to differentiate halos of glaucoma from cataract. If a stenopeic slit is passed across the pupil, glaucomatous halos remain intact, whereas cataractous halos break into segments. * **Differential Diagnosis of Halos:** Acute Congestive Glaucoma, Cataract, Mucopurulent Conjunctivitis (due to flakes of mucus on the cornea), and Corneal Edema (e.g., Fuch’s dystrophy). * **Key Distinction:** Halos in glaucoma are typically seen when the IOP exceeds 30-40 mmHg suddenly.

Q: A 30-year-old male with a family history of glaucoma presents with headache. On examination, intraocular pressure (IOP) is 22 mmHg in the right eye and 24 mmHg in the left eye. Angles were open on gonioscopy. No visual field defects were noted. What is the true statement regarding the management of this patient?

Ocular hypertension - no intervention required. ### Explanation This patient presents with **Ocular Hypertension (OHT)**. The diagnosis is based on the triad of: 1. **Elevated IOP** (>21 mmHg). 2. **Open angles** on gonioscopy. 3. **Absence of glaucomatous damage** (normal optic disc and normal visual fields). **Why Option C is correct:** According to the **Ocular Hypertension Treatment Study (OHTS)**, the risk of progression from OHT to Primary Open-Angle Glaucoma (POAG) is only about 1% per year. Therefore, routine medical intervention is not required unless specific high-risk factors are present (e.g., central corneal thickness 30 mmHg). In this 30-year-old with borderline pressures (22/24 mmHg) and no field defects, observation is the standard of care. **Why other options are incorrect:** * **Option A:** Normal Tension Glaucoma (NTG) requires IOP to be consistently $\leq$ 21 mmHg with evidence of optic nerve damage. This patient has elevated IOP and no damage. * **Option B:** POAG requires the presence of glaucomatous optic neuropathy or visual field defects. Since the fields are normal, this diagnosis is ruled out. * **Option D:** Treatment for OHT is generally reserved for patients with IOP >28–30 mmHg or those with significant risk factors. A pressure of 24 mmHg without damage does not mandate immediate treatment. ### High-Yield Clinical Pearls for NEET-PG: * **Gold Standard for IOP:** Goldmann Applanation Tonometry (GAT). * **Pachymetry:** Essential in OHT; thin corneas are a major risk factor for progression to glaucoma. * **OHTS Criteria for Treatment:** Start treatment if IOP >24 mmHg **AND** central corneal thickness is 30 mmHg. * **Follow-up:** OHT patients require annual visual field testing and disc evaluation.

Q: Gonioscopy is used to study:

The angle of the anterior chamber. **Explanation:** **Gonioscopy** is the clinical technique used to visualize the **angle of the anterior chamber**. Under normal conditions, the iridocorneal angle cannot be seen directly because light reflected from the angle undergoes **total internal reflection** at the tear-air interface (due to the critical angle of approximately 46°). A gonioscope (a specialized contact lens) eliminates this interface, allowing the clinician to assess the drainage structures. * **Why Option C is correct:** Gonioscopy is the gold standard for differentiating between **Open-Angle Glaucoma** and **Angle-Closure Glaucoma**. It allows for the visualization of structures such as Schwalbe’s line, trabecular meshwork, scleral spur, and ciliary body band. * **Why Options A & B are incorrect:** The anterior and posterior chambers are typically evaluated using a slit-lamp biomicroscope. While the anterior chamber depth is a precursor to angle assessment, gonioscopy specifically targets the *junction* (angle) where the iris meets the cornea. * **Why Option D is incorrect:** The retina is visualized using ophthalmoscopy (direct/indirect) or fundus biomicroscopy. **High-Yield Clinical Pearls for NEET-PG:** * **Goldmann 3-mirror lens:** Used for indirect gonioscopy and peripheral retina examination. * **Koeppe lens:** A prototype for direct gonioscopy (used in pediatrics/operating rooms). * **Shaffer’s Grading:** The most common system used to grade the angle width (Grade 0 to 4). * **Van Herick Technique:** A slit-lamp method to *estimate* angle depth, but it does not replace gonioscopy. * **Dynamic Gonioscopy (Indentation):** Used to differentiate between appositional closure and permanent synechial closure.

Q: Which of the following is NOT a system for the classification of the angles of the anterior chamber?

Sun Classification. The correct answer is **Sun Classification** because it is not a system used for grading the anterior chamber angle; rather, it is used to grade **anterior chamber cells** in uveitis (Standardization of Uveitis Nomenclature). ### Explanation of Options: * **Shaffer’s System:** The most commonly used classification in clinical practice. It grades the angle based on the **degree of openness** (from 0° to 45°) and the visibility of anatomical structures. Grade 0 is closed, while Grade 4 is wide open. * **Spaeth Classification:** A highly detailed system that assesses three parameters: the **level of iris insertion**, the **width of the angle** (in degrees), and the **configuration of the peripheral iris** (e.g., steep, regular, or concave). * **RPC (Redmond Smith, Scheie, and van Beuningen) Classification:** These are historical or specialized systems used to describe angle anatomy. The **Scheie system** is particularly high-yield, as it grades the angle based on the structures visible (Grade IV is closed, which is the opposite of Shaffer’s). ### High-Yield Clinical Pearls for NEET-PG: * **Gold Standard:** Gonioscopy remains the gold standard for angle evaluation. * **Shaffer vs. Scheie:** Remember that in **Shaffer**, Grade 4 is wide open. In **Scheie**, Grade IV is "closed" (no structures visible). * **SUN Criteria:** Always associate "SUN" with **Uveitis** grading (cells and flare), not Glaucoma. * **Van Herick Technique:** This is a slit-lamp method to *estimate* angle depth without a gonioscopy lens, comparing the peripheral corneal thickness to the depth of the peripheral anterior chamber.

Q: All of the following are causes of neovascular glaucoma except?

Central serous retinopathy. **Explanation:** Neovascular Glaucoma (NVG) is a secondary glaucoma caused by the formation of new vessels (neovascularization) on the iris (**rubeosis iridis**) and in the iridocorneal angle. This process is driven by **vascular endothelial growth factor (VEGF)**, which is released in response to chronic **retinal ischemia**. **Why Central Serous Retinopathy (CSR) is the correct answer:** CSR is characterized by the accumulation of subretinal fluid due to a leak in the retinal pigment epithelium. Unlike the other options, CSR is **not an ischemic condition**. Since there is no retinal hypoxia, there is no stimulus for VEGF production, making it a non-cause of NVG. **Analysis of Incorrect Options:** * **Diabetic Retinopathy:** Specifically Proliferative Diabetic Retinopathy (PDR), it is the most common cause of NVG. Extensive capillary non-perfusion leads to massive VEGF release. * **Central Retinal Vein Occlusion (CRVO):** Ischemic CRVO is the second most common cause. It is classically associated with **"100-day glaucoma"** (NVG typically appearing 3 months after the vascular event). * **Intraocular Tumors:** Tumors like Retinoblastoma (in children) or Uveal Melanoma (in adults) can cause NVG by inducing ischemia through mass effect or by secreting angiogenic factors. **Clinical Pearls for NEET-PG:** * **The "Big Three" causes of NVG:** 1. Diabetic Retinopathy, 2. Ischemic CRVO, 3. Carotid Artery Occlusive Disease. * **Pathogenesis:** VEGF → Rubeosis Iridis → Fibrovascular membrane contracts → Ectropion uveae and Synechial angle closure. * **Management:** Pan-retinal photocoagulation (PRP) is the gold standard to reduce the ischemic drive; Anti-VEGF injections are used as an adjunct.

Q: A 25-year-old young adult presented with painless red eye and an intraocular pressure of 60 mmHg. What is the most likely diagnosis?

Glaucomatocyclitic crisis. **Explanation:** The correct answer is **Glaucomatocyclitic crisis**, also known as **Posner-Schlossman Syndrome (PSS)**. **Why it is correct:** PSS typically presents in young adults (20–50 years) as recurrent, unilateral episodes of markedly elevated intraocular pressure (often 40–60 mmHg) with disproportionately mild symptoms. The hallmark is a **"painless red eye"** (or very mild discomfort/blurring) despite the massive IOP spike. Clinical findings include mild ciliary congestion, a few fine "stellate" keratic precipitates (KPs) on the endothelium, and an open angle on gonioscopy. The pressure rise is due to acute trabeculitis. **Why other options are incorrect:** * **Chronic papilledema:** This involves optic disc swelling due to increased intracranial pressure. It does not cause elevated intraocular pressure or a red eye. * **Acute angle closure glaucoma (AACG):** While IOP is very high, AACG is a medical emergency characterized by **severe pain**, nausea, vomiting, a hazy cornea, and a shallow anterior chamber. It rarely occurs in a 25-year-old unless there is a predisposing anatomical factor (e.g., nanophthalmos). * **Acute anterior uveitis:** While this causes a red eye, the IOP is typically **low or normal** due to ciliary body hyposecretion. If the IOP is high (hypertensive uveitis), it is usually accompanied by significant pain and photophobia, unlike the "painless" presentation of PSS. **High-Yield Clinical Pearls for NEET-PG:** * **Triad of PSS:** Unilateral high IOP + Open angles + Fine stellate KPs. * **Treatment:** Medical management with topical steroids (to control inflammation) and aqueous suppressants (to lower IOP). Miotics (Pilocarpine) are avoided. * **Prognosis:** Excellent, as the episodes are self-limiting, though long-term monitoring is required for permanent glaucomatous damage.

Question 1

What type of laser is used in laser iridotomy?

Accepted Answer

Nd Yag laser

Answer

CO2 laser

Answer

Excimer laser

Answer

KTP laser

Question 2

A 60-year-old woman with primary open-angle glaucoma presents with a specific visual field defect. Which part of the visual field is most resistant to progressive glaucomatous visual field loss?

Accepted Answer

Temporal peripheral vision

Answer

Central vision

Answer

Nasal peripheral vision

Answer

Superior vision

Question 3

What is the preferred drug for acute angle closure glaucoma?

Accepted Answer

Pilocarpine

Answer

Beta-blocker

Answer

Atropine

Answer

None of the above

Question 4

A coloured halo is seen in all conditions except:

Accepted Answer

Open angle glaucoma

Answer

Closed angle glaucoma

Answer

Cataract

Answer

None of the above

Question 5

A 30-year-old male with a family history of glaucoma presents with headache. On examination, intraocular pressure (IOP) is 22 mmHg in the right eye and 24 mmHg in the left eye. Angles were open on gonioscopy. No visual field defects were noted. What is the true statement regarding the management of this patient?

Accepted Answer

Ocular hypertension - no intervention required

Answer

Normal tension glaucoma to be treated

Answer

Primary open-angle glaucoma to be treated

Answer

Ocular hypertension to be treated

Question 6

Gonioscopy is used to study:

Accepted Answer

The angle of the anterior chamber

Answer

Anterior chamber

Answer

Posterior chamber

Answer

Retina

Question 7

Which of the following is NOT a system for the classification of the angles of the anterior chamber?

Accepted Answer

Sun Classification

Answer

Spaeth

Answer

RPC classification

Answer

Shaffer's system

Question 8

All of the following are causes of neovascular glaucoma except?

Accepted Answer

Central serous retinopathy

Answer

Diabetic retinopathy

Answer

Intraocular tumour

Answer

Central retinal vein occlusion

Question 9

All of the following are true statements with respect to angle closure glaucoma EXCEPT:

Accepted Answer

Vogt's triad is indicative of an acute active attack of angle closure glaucoma

Answer

Does not cause ocular pain at evening/night

Answer

Bullous keratopathy and shallow anterior chamber may be seen

Answer

Intravenous Mannitol is the drug of choice for angle closure glaucoma

Question 10

A 25-year-old young adult presented with painless red eye and an intraocular pressure of 60 mmHg. What is the most likely diagnosis?

Accepted Answer

Glaucomatocyclitic crisis

Answer

Chronic papilledema

Answer

Acute angle closure glaucoma

Answer

Acute anterior uveitis

Glaucoma — MCQs

Glaucoma — MCQs

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